#include <cmath>
#include <cstdio>
#include <iostream>
#include <utility>
#include <algorithm>
#include <vector>
using namespace std;
void dfs(int i,vector<int>&depth,vector<int>&parent,vector<vector<int> >&a,vector<bool>&v,int p){
v[i]=true;
depth[i]=1+depth[p];
parent[i]=p;
for(int c:a[i]){
if(!v[c])
dfs(c,depth,parent,a,v,i);
}
}
int ide(int a,int b,vector<vector<pair<int,int> > >&ref){
if(a>b)swap(a,b);
for(int i=0;i<ref[a].size();i++){
if(ref[a][i].first==b)
return ref[a][i].second;
}
}
void conectar(int a,int b,vector<int>&d,vector<int>&p,vector<int>&con,int k,vector<int>&r,vector<vector<pair<int,int> > >&ref,vector<bool>&v){
if(d[a]<d[b])swap(a,b);
while(d[a]!=d[b]){
int pa=p[a];
int id=ide(pa,a,ref);
if(!v[id]){
con[id]++;
v[id]=true;
if(con[id]==k){
r.push_back(id);
}
}
a=pa;
}
while(a!=b){
int pa=p[a];
int pb=p[b];
int id=ide(pa,a,ref);
if(!v[id]){
con[id]++;
v[id]=true;
if(con[id]==k && pa!=a){
r.push_back(id);
}
}
id=ide(pb,b,ref);
if(!v[id]){
con[id]++;
v[id]=true;
if(con[id]==k && pa!=a){
r.push_back(id);
}
}
a=pa;
b=pb;
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
int n,k,m,x,y,j;
cin>>n>>m>>k;
vector<vector<pair<int,int> > >ref(n);
vector<vector<int> >a(n);
for(int i=0;i<n-1;i++){
cin>>x>>y;
x--;
y--;
if(x>y)swap(x,y);
ref[x].push_back(make_pair(y,i+1));
a[x].push_back(y);
a[y].push_back(x);
}
vector<int>depth(n,0);
vector<int>parent(n,0);
vector<bool>v(n,false);
dfs(0,depth,parent,a,v,0);
vector<int>con(n+1,0);
vector<int>r;
for(int i=0;i<m;i++){
cin>>j;
cin>>x;
x--;
v.assign(n+1,false);
for(int o=1;o<j;o++){
cin>>y;
y--;
conectar(x,y,depth,parent,con,k,r,ref,v);
y=x;
}
}
sort(r.begin(),r.end());
cout<<r.size()<<"\n";
for(int i=0;i<r.size();i++){
cout<<r[i]<<" ";
}
return 0;
}
